Spring for composite sealing ring and method of manufacture

ABSTRACT

A spring for a composite sealing ring of the type having a channel-shaped jacket. The spring comprises an annular member of U-shaped cross section, the web of the U engaging the web of the jacket, the flanges of the U pressing against the flanges of the jacket and having a plurality of circumferentially spaced slots. In one form, useful primarily for radial seals, the spring comprises a sinuous member bent to form the web and flanges. In another form, useful for face seals, the web is circumferentially continuous and the flanges are formed by spaced legs. The spring is fabricated by first forming it in flat shape and then bending the flanges out of the plane of the web. The flat blank may be made by a photoetch process or, in the case of the sinuous embodiment, bending a wire into sinuous shape, flattening the wire and then bending the flanges away from the web.

United States Patent [1 1 Evans et al.

1 Sept. 24, 1974 SPRING FOR COMPOSITE SEALING RING AND METHOD OFMANUFACTURE [75] Inventors: Bryce B. Evans, Jackson, Mich.;

Edwin C. Elsner, Kanosh, Utah [73] Assignee: Aeroquip Corporation,Jackson,

Primary Examiner-James B. Marbert Attorney, Agent, or Firm-Harness,Dickey & Pierce 'III [5 7] ABSTRACT A spring for a composite sealingring of the type having a channel-shaped jacket. The spring comprises anannular member of U-shaped cross section, the web of the U engaging theweb of the jacket, the flanges of the U pressing against the flanges ofthe jacket and having a plurality of circumferentially spaced slots. Inone form, useful primarily for radial seals, the spring comprises asinuous member bent to form the web and flanges. In another form, usefulfor face seals, the web is circumferentially continuous and the flangesare formed by spaced legs. The spring is fabricated by first forming itin flat shape and then bending the flanges out of the plane of the web.The flat blank may be made by a photoetch process or, in the case of thesinuous embodiment, bending a wire into sinuous shape, flattening thewire and then bending the flanges away from the web.

8 Claims, 17 Drawing Figures Pmaminww 3.837; 631

SPRING FOR COMPOSITE SEALING RING AND METHOD OF MANUFACTURE BACKGROUNDOF THE INVENTION 1. Field of the Invention The invention relates toseals, and more particularly to composite sealing rings of the typehaving an annular flexible sealing jacket of channel-shaped crosssection the flanges of which engage the surfaces to be sealed, and anannular spring disposed within the jacket and pressing against saidjacket flanges. In such sealing rings, the jacket may be made of amaterial such as Teflon which can perform a sealing function atrelatively high temperatures, and the spring is fabricated of a metalwhich will maintain a constant sealing force over long periods of time.

2. Description of the Prior Art In prior art sealing rings of this type,as exemplified by Reid US. Pat. No 3,223,426, the spring is a helicallycoiled spring formed of a flat ribbon-like strip of spring material. Ithas been found that this construction has certain disadvantages,particularly where it is desired to fabricate sealing rings of smallerdiameters. In such instances, the helically coiled spring presents toomuch stiffness and is incapable of sufficient flexing for efficientinstallation and use. Moreover, in order to form a complete loop withthe helically coiled spring, it is necessary to weld the spring endstogether which may be a time-consuming and expensive operation.

BRIEF SUMMARY OF THE INVENTION It is an object of the present inventionto provide a novel and improved spring construction for compositesealing rings which provides sufficient flexibility to make it usable insealing rings of relatively small diameters, without detracting from theefficiency of the spring for its intended purpose.

It is another object to provide an improved spring for composite sealingrings which may be utilized both for radial and face seals, and whicheliminates in most cases the need for welding or otherwise attaching thespring ends.

It is also an object to provide an improved spring of the characterwhich is relatively simple and inexpensive to fabricate.

It is another object to provide a method of manufacturing a spring forcomposite sealing rings which utilizes easily available materials andtools, and is thus economical to practice.

It is a further object to provide an improved spring of this type whichis especially adapted for small diameter seals.

It is another object to provide a novel and improved spring of thischaracter which lessens the possibility of the spring in a compositesealing ring popping out of its jacket when being installed in position.

Briefly, the invention comprises an annular spring having a U-shapedcross section, the web of the U resting against the web 'of the jacketand the flanges pressing outwardly against the flanges of the jacket andhaving circumferentially spaced slots which allow limited adjustmentwhen installing the spring in the jacket.

In one form, the spring has a sinuous shape so that the web as well asthe flanges are provided with slots. This form is especially adapted foruse in radial sealing rings. In another version, the web is continuousbut the flanges comprise fingers which extend outwardly in oppositedirections. This embodiment is particularly adapted for use in faceseals.

The spring may be made from a flat blank which is cut to proper length.The flanges are bent out of the plane of the web and the spring theninstalled in the jacket. In either version, the flat blank may be formedby a photoetch process. The blank for the sinuous form may alternativelybe fabricated by bending a wire of round cross section into sinuousshape, flattening the wire and then cutting it to proper length to matchthe circumference of the jacket.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary plan view ofthe flat blank used to fabricate the sinuous form of the spring;

FIG. 2 is a side elevational view looking in the direction of the arrow2 of FIG. 1;

FIG. 3 is a cross-sectional view taken along the line 33 of FIG. 4 andshowing the spring after the flanges have been bent out of the plane ofthe web;

FIG. 4 is a fragmentary front elevational view of the spring beforeinsertion in the jacket;

FIG. 5 is a front elevational view of a radial composite sealing ringutilizing the spring of this invention;

FIG. 6 is an enlarged fragmentary cross-sectional view taken along theline 6-6 of FIG. 5 and showing the position of the spring in the jacket;

FIG. 7 is a fragmentary plan view in schematic form showing how thesinuous form of the invention may be fabricated using a wire;

FIG. 8 is a side elevational view of the spring of FIG. 7 looking in thedirection of the arrow 8 thereof;

FIG. 9 is an end elevational view of FIG. 7 looking in the direction ofarrow 9;

FIG. 10 is a fragmentary plan view of the flat blank used to form asecond embodiment of the invention, especially useful in face sealingrings;

FIG. 11 is an end elevational view taken in the direction of the arrow11 of FIG. 10;

FIG. 12 is a fragmentary cross-sectional view in elevation showing thespring of FIGS. 10 and 11 in final form and installed in its jacket;

FIG. 13 is a fragmentary side view in elevation showing theconfiguration of the fingers; and

FIGS. 14, 15, 16 and 17 are fragmentary elevational views, partly incross section, showing different ways in which the ends of the springmay be attached to each other if necessary.

DESCRIPTION OF THE PREFERRED EMBODIMENTS A composite sealing ring inwhich the invention is used is indicated generally at 11 in FIGS. 5 and6, the illustrated sealing ring being of a radial type to seal betweenan inner member partially indicated at 12 and an outer member partiallyindicated at 13. The sealing ring comprises a jacket generally indicatedat 14 and a spring generally indicated at 15. The jacket is annular andof channel-shaped cross section, being fabricated of a material such asTeflon which has the desired flexing, sealing, wear andtemperature-resistant qualities. This jacket has a central web 16 andinner and outer flanges 17 and 18. Flange 17 has an annular protuberancel9 engaging part 12 and flange 18 carries a similar protuberance 21engaging part 13. The sealing ring is placed between the parts in such amanner that its open side is exposed to pressure of fluid between thesurfaces thereof.

The purpose of spring is to resist deformation of the jacket and exertradial forces on flanges 17 and 18. The spring is of annular shape andfits within the pocket 22 formed by jacket 14. Spring 15 is fabricatedof a spring-like material such as stainless steel or any of a number ofother materials having appropriate resilient qualities. The spring has aU-shaped cross section with a central web generally indicated at 23 andinner and outer flanges generally indicated at 24 and respectively. Web23 rests against web 16 of jacket 14 whereas flanges 24 and 25 engageflanges 17 and 18 respectively.

Spring 15 has a sinuous shape as shown in FIGS. 1 through 4, such thatspaces 26 appear in flange 24 and spaces 27 in flange 25. These spacesare sufficiently narrow as to prevent the material of jacket 14 fromappreciably extruding into the spaces during operation.

Spring 15 is preferably fabricated by first forming a flat blankgenerally indicated at 28 in FIGS. 1 and 2, and then bending this blankto form the web 23 and flanges 24 and 25 as seen in FIGS. 3 and 4. Onemethod of making flat blank 28 is by the conventional photoetch process.In this method a sheet of spring-like metal is sensitized on one surfaceand exposed to light of an appropriate pattern. The sheet is then dippedin acid which will etch away certain portions of the metal, leaving theflat blank shown in FIGS. 1 and 2. The photoetch process is especiallyuseful where springs for relatively small diameter sealing rings arebeing manufactured. Blank 28 is cut to a length corresponding to thecircumference of the jacket slot 22 and is then bent to the form shownin FIGS. 3 and 4 so that web 23 will approximate the inside surfaceshape of jacket web 16 and flanges 24 and 25 will lie flat againstflanges 17 and 18 respectively when the seal is mounted in position.Alternatively, the spring length could be determined after the flangesare bent from the web. In most cases, the ends of the spring merely abuteach other after insertion in the slot, although other methods offastening the ends are discussed below.

It will be seen from the figures that flanges 24 and 25 are each made upof a plurality of U-shaped legs forming the spaces 26 and 27therebetween, and that web 23 likewise has spaces 29. These spaces willfacilitate insertion and curving of the spring around groove 22, itbeing preferred that the neutral axis of bending be approximately equalto the circumferential length of the groove so that spaces 26 willslightly contract and spaces 27 slightly expand during formation of thespring. The thickness and dimensions of the spring material may, ofcourse, be varied to suit the particular force and other requirements.The abutment between the spring ends is indicated at 30 in FIG. 4.

The operation of spring 15 will be apparent from FIG. 6. Flexing of thespring will occur mainly along web 23 and the junctions 31 and 32between this web and flanges 24 and 25 respectively. Thus, whileadequate forces will be constantly exerted on portions 19 and 21 ofjacket 14 to create the sealing action, there will be sufficientflexibility in the entire assembly to permit insertion between theparts. This will be especially useful when relatively small diametersare involved, since it has been found that the conventional helicallycoiled spring in the aforementioned US. Pat.

No. 3,223,426 is frequently too stiff to permit proper installation.

FIGS. 7, 8 and 9 illustrate another method of manufacturing a flat blankfor the spring shown in FIGS. 5

and 6. According to this method, a soft workhardenable grade of roundwire indicated in dot-dash lines at 33 is formed into sinuous shape withrelatively long parallel legs connected by short arcuate portions. It isthen flattened to the thickness and shape shown in solid lines in FIGS.8 and 9. This will leave legs 34 connected by bridges 35, with spaces36. The initial diameter of the wire, its pitch during the sinuousbending, and the thickness to which it is flattened are all controlledso that the resulting growth after flattening will close gaps 36 to thedesired dimensions. Moreover, during the flattening process the softwire will work to spring hardness eliminating the requirement for heattreatment. The material grain structure will also follow the originalaxis of the wire which is ideal for the spring as it is used.

FIGS. 10 through 13 illustrate a second embodiment of the inventionwhich is basically similar to the first embodiment but in which the webportion of the spring is continuous. As seen in FIG. 12, the spring isgenerally indicated at 101 and is of annular construction with aU-shaped cross section, having a web generally indicated at 102 and apair of flanges generally indicated at 103 and 104. For reasons whichwill become apparent, this embodiment of the spring is especiallyadapted for composite sealing rings which are used as face rather thanradial seals. Such a ring is generally indicated at 105 in FIG. 12 andcomprises a jacket generally indicated at 106 having ridges 107 and 108engag ing parts 109 and 111 respectively.

Spring 101 is formed from a flat blank generally indicated at 112 inFIGS. 10 and 11. This blank, which may be fabricated by theabove-described photoetch process, comprises a continuous centralportion 113 and a plurality of outwardly extending fingers 114 withspaces 115 therebetween. Fingers 114 are bent so as to form flanges 103and 104, and the blank cut to the desired length matching thecircumference of the jacket slot.

To install spring 101, one end will be inserted in the slot and theremainder of the spring progressively inserted. The ends will abut asindicated at 116 in FIG. 13. Welding or otherwise attaching the springends will normally be unnecessary because web 102 is supported by thejacket web and will thus not change its curvature. Flanges 103 and 104will constantly urge portions 107 and 108 of the jacket against theirrespective parts 109 and 111.

FIG. 13 illustrates the shape of flanges 103 and 104 when the spring isinstalled. It will be noted that spaces 115 between the fingers 114 willbe narrowed as web 102 flexes to engage the web of jacket 106.

FIGS. 14, 15, 16 and 17 show various ways in which the ends of a springmay be secured if this becomes necessary in any particular installation.FIG. 14 shows a spring 201 with its abutting ends welded as indicated at202. FIGS. 15 and 16 show a spring 301 having a notch and dovetailconnection 302, 303. FIG. 17 shows a spring 401 in which the abuttingends are stapled as indicated at 402.

We claim:

1. A spring for a composite sealing ring of the type having an annularflexible sealing jacket of channelshaped cross section with a web and apair of flanges engaging the parts to be sealed, said spring comprisingan annular member of U-shaped cross section having a flat web engagingthe web of said jacket and a pair of flat flanges engaging and pressingoutwardly on the flanges of said jacket, said web being as wide as andconforming to the shape of the bottom of said jacket channel, wherebythe flange portions adjacent said web will be at least as far apart astheir portions remote from said web when the ring is installed in saidchannel, said flanges having circumferentially spaced slots and engagingthe walls of said jacket channel from their portions adjacent to theirportions remote from the channel bottom, said spaces being substantiallynarrower than the portions of said spring between said spaces so as toprevent said jacket from appreciably extruding into said spaces duringoperation.

2. A spring for a composite sealing ring of the type having an annularflexible sealing jacket of channelshaped cross section with a web and apair of flanges engaging the parts to be sealed, said spring comprisingan annular member of U-shaped cross section having a web engaging theweb of said jacket and a pair of flanges engaging and pressing outwardlyon the flanges of said jacket, said flanges having circumferentiallyspaced slots, said spring bei'ng fabricated of a flat member whichextends sinuously through both flanges and the web, whereby said slotswill extend from alternate flanges through said web, each slot extendingcompletely through one flange and said web and partially through theother flange, the slots being substantially narrower than said web andflanges and sufficiently narrow as to prevent appreciable extrusion ofthe jacket material into the slots during use.

3. The combination according to claim 2, the ends of said spring beingin abutting relation.

4. The combination according to claim 2, the ends of said spring beingin abutting relation and welded together.

5. The combination according to claim 2, the ends of said spring beingin abutting relation and having a slot and dovetail connection.

6. The combination according to claim 2, the ends of said spring beingin abutting relation and stapled together.

7. The combination according to claim 1, said spring being fabricatedfrom a flat blank having a continuous central portion and oppositelyextending fingers with said slots therebetween, said fingers being bentto form the flanges with the continuous portion forming the web.

8. The combination according to claim 7, the ends of said spring beingin abutting relation.

1. A spring for a composite sealing ring of the type having an annularflexible sealing jacket of channel-shaped cross section with a web and apair of flanges engaging the parts to be sealed, said spring comprisingan annular member of U-shaped cross section having a flat web engagingthe web of said jacket and a pair of flat flanges engaging and pressingoutwardly on the flanges of said jacket, said web being as wide as andconforming to the shape of the bottom of said jacket channel, wherebythe flange portions adjacent said web will be at least as far apart astheir portions remote from said web when the ring is installed in saidchannel, said flanges having circumferentially spaced slots and engagingthe walls of said jacket channel from their portions adjacent to theirportions remote from the channel bottom, said spaces being substantiallynarrower than the portions of said spring between said spaces so as toprevent said jacket from appreciably extruding into said spaces duringoperation.
 2. A spring for a composite sealing ring of the type havingan annular flexible sealing jacket of channel-shaped cross section witha web and a pair of flanges engaging the parts to be sealed, said springcomprising an annular member of U-shaped cross section having a webengaging the web of said jacket and a pair of flanges engaging andpressing outwardly on the flanges of said jacket, said flanges havingcircumferentially spaced slots, said spring being fabricated of a flatmember which extends sinuously through both flanges and the web, wherebysaid slots will extend from alternate flanges through said web, eachslot extending completely through one flange and said web and partiallythrough the other flange, the slots being substantially narrower thansaid web and flanges and sufficiently narrow as to prevent appreciableextrusion of the jacket material into the slots during use.
 3. Thecombination according to claim 2, the ends of said spring being inabutting relation.
 4. The combination according to claim 2, the ends ofsaid spring being in abutting relation and welded together.
 5. Thecombination according to claim 2, the ends of said spring being inabutting relation and having a slot and dovetail connection.
 6. Thecombination according to claim 2, the ends of said spring being inabutting relation and stapled together.
 7. The combination according toclaim 1, said spring being fabricated from a flat blank having acontinuous central portion and oppositely extending fingers with saidslots therebetween, said fingers being bent to form the flanges with thecontinuous portion forming the web.
 8. The combination according toclaim 7, the ends of said spring being in abutting relation.